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Rhodoland |
The word Rhododendron is from Greek origin - the word 'Rhodo' means
Rose, the word 'Dendron' means tree,so together 'Rose tree'. They
belong to the genus Rhododendron, as the Azaleas. This genus belongs to
the family of the Ericaceae to which also belong the heathers Calluna
and Erica, and f.i. Gaultheria and Vaccinium etc. It is a very large
family of which the genus Rhododendron consists of about 1.000, yes
about one thousand species. The origin of most of them is Asia, China,
Japan and Korea, but also the Caucasus (R. caucasicum) and Asia Minor,
(R. smirnovii). In the Swiss and Austrian Alps we find the species R.
ferrugineum and R. hirsutum And in North-America, most in the USA, .there are alo some Rhododendron, like the R. catawbiense on the east coast and the R. macrophyllum on the west coast. . Also a number of fine native Azaleas, like R. occidentale on the west coast and many others more on the (south)east side of the USA. Examples are R. arborescens, R. calendulaceum and R. atlanticum. Many are fragrant, also the hybrids. More and more they are getting the attention they deserve. |
The Rhododendrons we see and plant in our gardens are mostly hybrids, bred
out of the original species. This hybridizing work started mainly in
Europe, first in England, later also in Belgium, Germany and the
Netherlands. English, but also Dutch, French and German planthunters
introduced many species from Asia to Europe. Names as George Forrest and
Frank Kingdon Ward and many others should be honoured for their
contribution! Many plant lovers hybridized with them since the end of the
18th century and introduced thousands of new hybrids. Later also American
hybridizers brought many new hybrids into trade and still do with
excellent new introductions. |
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Division
Classification of the genus Rhododendron is an extremely difficult issue. Scientists are still not certain about the right 'division' in series and species etc. For easy of survay we can divide the genus Rhododendron in 4 main groups, of which you find some images and short dexcriptions:
Large leaved Rhododendron:
The large leaved species and hybrids have mostly also large flowers, that's clear. These species and hybrids we call 'elepidote', which means that they have no scales on the underside of their leaves. There are even species with very long leaves, up to 3 feet, like R. macabeanum and R. sinogrande. They can be grown in mild climates as in west Scotland. Some species like R. yakushimanum have a sort of thick wooly felt on the underside of the leaves. We call this felt 'Indumentum'. It is ment for protection from frost and heat.
Small leaved Rhododendron:
We call the small leaved Rhododendron 'lepidote'; they have small scales on the underside of the leaves. You can smell the leaves by crushing them. Walking through a greenhouse with some R. concinnum you can smell a very nice aromatic odeur. The flowers are also smaller than those of the elepidote Rhododendron. Many species of this group have lilac, pink or blue flowers, that's why some people call them 'the small blues'. Some of them have variable colours, like R. augustinii with pink, lilac, blue or almost white flowers. Though many lepidote species are low growing, or even creeping like R. keiskei Var. cordifolia, some can grow quite tall, up to 10 feet., like R. augustinii or R. concinnum. I have a quite special species in my garden, R. cinnabarinum Var. blandfordiiflorum, which is already about 7 feet and has nice yellow-orange tubular flowers.
Evergreen Azaleas
The group of evergreen azales has now also some thousands of named hybrids and
every year many more are introduced. They have small leaves up to 2 inches and
mostly small flowers. In wintertime most of the spring leaves drop off and the
summer leaves remain. With heavy frost even many of them drop off. Then they
need protection from cold and dry winds. Some varieties have nice bronze red
leaves in winter, making a nice contrast with some snow. Others like 'Haru no
Sono' a Satsuki azalea, have fine dark green glowing leaves. Satsuki azaleas are
from Japan, bred for their patterns of striped and flecked flowers.
There are no really yellow or orange flowers in this group, but some hybridizers
are working on it........
Deciduous azaleas:
Deciduous azaleas loose their leaves in fall and so in winter they are bare. Some have nice flower buds. Last 2 centuries many hybridizers, in the beginning especcially Belgians, created many fine new hybrids out of the original species from Asia and America. Some with double and fragrant flowers. Nowadays American and some German hybridizers are trying to get more fine hybrids, involving the native azaleas in the USA. Many plants have very nice fall colours of almost red, bronze, orange and yellow leaves. They have many bright colours, also real yellow and orange. Most are frost hardy, some groups even to - 35F, -40C.
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